Problem: Solve for $x$ and $y$ using substitution. ${-4x-y = -6}$ ${y = -5x+5}$
Explanation: Since $y$ has already been solved for, substitute $-5x+5$ for $y$ in the first equation. ${-4x - }{(-5x+5)}{= -6}$ Simplify and solve for $x$ $-4x+5x - 5 = -6$ $x-5 = -6$ $x-5{+5} = -6{+5}$ ${x = -1}$ Now that you know ${x = -1}$ , plug it back into $\thinspace {y = -5x+5}\thinspace$ to find $y$ ${y = -5}{(-1)}{ + 5}$ $y = 5 + 5$ $y = 10$ You can also plug ${x = -1}$ into $\thinspace {-4x-y = -6}\thinspace$ and get the same answer for $y$ : ${-4}{(-1)}{ - y = -6}$ ${y = 10}$